Rotary-pump pressure control



,March 11, 1924; 1,48%,836

E. HILL 7 ROTARY PUMP PRESSURE CONTROL Filed April 28 192s r1 G l /22 A TTORNEY Patented Mar. 11, 1924. V

EBENEZER HILIQOF. SOUTH NORWALK, CONNECTICUT, ASSIG-NOR TO THE HILL COM- PRESSOR & PUMP COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

ROTARY-PUMP PRESSURE CONTROL.

Application filed April 28, 1923. Serial Np. 635,372.

To all whom it may concern:

Be it known that I, EBENEZER HILL, a citizen of the United States, residing at South Norwalk, in the county of Fairfield and State of Connecticut, have invented a new and useful Improvement in Rotary- Pump Pressure Controls, of which the following is a specification.

This invention relates generally to rotary pumps, compressors, and similar apparatus hereinafter termed pumps, comprising an outer member and an inner member, one of which is rotatable with relation to the other, which pumps are particularly adapted for pumping and exerting pressure on fluids, and it relates more particularly -to that type of pump having an outer driving gear intermeshing with an inner driven gear, the inner driven gear having a different numberof teeth than, and being eccentrically mounted within, the outer gear. A pump of this type is shown and described in my copending application Serial No. 594,028, filed October 12, 1922.

The object of the invention is to provide a simple pressure governing and sealing mechanism for such pumps, which not only controls the discharge pressure and readily admits of regulation of that pressure but also utilizes the pressure to keep the pump tight and prevent leakage of the fluid across the side faces of the compressing members, no matter to what degree the pressure is raised, or reduced, with respect to atmospheric pressure.

This object is attained by arranging, within the pump casing, .a plate which is non-rotatable but is movable laterally toward the adjacent faces of the compressing members, and is forced against them by the discharge pressure of the pump, and by providing this plate with intake and discharge ports through which the fluid enters into, and is discharged from, the spaces between the compression members, which compression members have a rotatable adjustment whereby the position of the intake and compression spaces may be altered with relation to the intake and discharge ports of the plate to obtain the desired pressure in the compression spaces and to vary the terminal or discharge pressure at the end of the compression cycle, and by providing means, automatically or manually o erated, by which this adjustment may bee ected.

In the accompanying drawings Fig. 1 shows a longitudinal section of "one preferred form of pump which embodies the invention. Fig. 2 is a transverse section of this form of pump, on the dotted lines 2--2 on Fig. 1 showing co-operating gears. Fig. 3 is a transverse section on the dotted line 33 on Fig. 1, showing the valve and sealing plate. Fig. 4 is a view looking toward one endof the pump with an automatic pressure control in section.

The pump casing 5 is cylindrical and has a head 6 secured in such manner that the head may be removed to give access to the interior of the casing. The casing has a hub 7 and the head has a hub 8. In the side of the casing shown is an intake opening 9 and in the face of the casing is a discharge opening 10.

The outer gear 11 has its periphery shaped so that it will have a close but rotatable fit within the casing. The teeth 12 of this gear are curved as are the spaces 13 between the teeth. The outer gear is shown as attached to a driving shaft M that extends through the hub 8 of the head. The shaft is mounted on bearings 15 in the head and is made tight by ordinary packing 16 in the hub.

The inner gear 17 has curved teeth 18 and curved spaces 19 between the teeth. This gear is mounted on an arbor 20, with interposed bearings 21. The axis of the inner gear is eccentric to the axis of the outer gear. The inner gear is of such diameter and its eccentricity is such that when a tooth 23 on one side bottoms closely in a space between the teeth 24 of the outer gear, the tooth 25 on the inner gear opposite this will just clear the adjacent tooth 26 of the outer gear at the crest contact point of the gears, the diameters of the gears, the shapes of the teeth and the amount of eccentricitybeing designed to permit of all remaining teeth of one gear contacting the corresponding teeth of the other gear at varying interdental depths, as shown in Figs. 2 and 3. With this construction as the gears rotate, the spaces between the teeth, from the bottoming tooth 23 to the sealing teeth 25, 26, increase in capacity while the spaces between the teeth from the sealing teeth 25, 26, to the bottoming tooth 23 decrease in capacity, and a close seal is made between the adjacent spaces by the contact of the teeth of the gears from the sealing teeth around to the bottoming teeth.

The fluid is allowed to enter the suction spaces 60 which are on the one side of the crest contact point 25, 26, and is discharged from the compression spaces 61 which are on the other side. As the rotation of the gears progresses the volume oi fluid 'increases on the suction side owing to the increase in size of the spaces between the teeth, and decreases on the discharge side owing to the decrease in size of the spaces on that side. Consequently any fluid which is drawn in on the suction side is compressed on the discharge side. The pressure to which the fluid can be compressed is controlled by the distance of the discharge port on the compression side of the pump from the crest contact point 25, 26.

The plate 22, the circular periphery of which is provided with piston rings 70, snugly fitting the circular wall of the chamber 1n the casing to form a substantially gas tight joint between the plate and the casing, has an intake chamber 27'opposite the intake opening 9 through the casing, and holes 28, through the side wall of the intake chamber which open into the suction spaces 60, on the intake side. The plate has a discharge port 29, which opens out of the compression spaces 61, on the discharge side. The plate 22 is free to move laterally or sidewise in the casing to establish a tight contact with the side faces of the gears and a space 30 is left between it and the wall of the casing, which space is in communication with the discharge port so that the pressure of the compressed fluid which has entered said space will be exerted against the back or outer face of the plate and force it tightly against the side faces of the gears.

In the form of the pump shown the plate 22 is secured against rotation in the casing but is movable toward the gears. This may be accomplished by fitting the angular hub of the plate in an angular socket in the casing. In the hub 7 of the casing and suitably packed to prevent leakage is a spindle 31, which passes through the plate 22 and is connected with the arbor 20. The spindle 31 is in axial alignment with the shaft 14 but the arbor 20 which is a part of the spindle 31 is eccentric to the shaft and spindle. The outer end of the spindle may be provided with a lever 32 which can be operated manually for turning the spindle and rotatably adjusting the angular relation of the gears within the casing and thus varying the position of the intake and compression spaces with relation to the discharge port 29 of the plate 22. It is preferred however to connect this lever by a link 33 with a piston 34 in a cylinder 35 which is designed to be connected by a pipe 36 with the pipe 37 that leads from the Leeasao discharge port 10 to the receiver 37 into which the apparatus discharges. The pres sure of the fluid on the piston 34 is resisted by a spring 38 which returns the piston towards its startin position as the pressure decreases and a p ug 39 is arranged back of the spring so that its tension may be varied. A stop screw 40 is arranged back of the .lever in such position that the distance of movement of the lever under the pressure in the cylinder can be accurately limited.

The pressure to which the fluid will be compressed depends on how far around the compression side 61 the discharge port is located from the crest contact point of the gears. The further around in the direction of the arrows, Figs. 2 and 3, the edge 41 of the discharge port in the plate 22 is located from the crest contact point, the greater will be the discharge pressure, for the spaces on the compression side of the pump between the teeth of the gears decrease and the volume of fluid is consequently reduced until it can escape through the discharge port. The discharge port in the plate 22 is made in the shape of an arcuate slot of sufficient length to simultaneously open two or more of the spaces between the gear teeth so that any fluid in the compression spaces beyond the point at which it is desired to take off the fluid may escape, and not be carried to a higher pressure than is desired on account of not being able to get out. Thus the position of the compression space to the edge 41 of the discharge port determines the terminal or discharge pressure.

The pressure on the back of the plate 22' causes the plate to hug the faces of the teeth and follow up any wear, and reduces the amount of oil or lubricant necessary for a seal. The spindle 31 when turned in the direction of rotation of the gears brings the crest contact point 25, 26 nearer the edge 41 of the discharge port 29 and decreases the discharge pressure through that port and when turned in the direction opposite to the rotation of the gears increases the discharge pressure. In the form of pump described, if the pressure in the reservoir into which the gas is pumped is low it is not necessary to carry the compression in the pump to a higher degree for that would take more power and on release through the port the fluid would merely expand into the reservoir at the lower pressure. If the discharge occurs at such a point that the pressure in the pump is equal to the reservoir pressure then the pump will compress to exactly the pressure being used. As the reservoir pressure increases, the position of the compression spaces with reference to the discharge port is changed slightly in the direction opposite to the rotation of the gears to meet the altered conditions of pressure, so that the terminal pressure in the compression s aces and the pressure in the reservoir wil always be the same. The tension of the spring in the governor cylinder is set to the required degree. When the pressure of the fluid on the piston increases,

the piston is pressed against and compresses the spring and this movement of the piston,

through the link and lever rotatably adjusts the gears and changes the relation of the compression spaces 61 to the discharge port 29, in the direction opposite to rotation of the gears, until arrested by the stop 40.

This rotatable adjustment increases the discharge pressure of the pump. This can continue until the pressure in the reservoir reaches such a degree that the piston is pushed back far enough for the lever to be obstructed by'the stop 40. With this governing arrangement the pump is required to compress only to the reservoir pressure and consequently will run with a minimum of power. As the pressure builds up in the reservoir this rotatable adjustment of the gears is automatically continued so that the pump will deliver fluid at a proportionately greater pressure. A number of these pumps can be used in series if desired to obtain a very highpressure.

By holdin the plate 22 against rotation and adjusta 1y rotating the compression. members the point of tangency of the .pitch circles of the inner and outer gears may be changed with reference'to the discharge port in the plate 22 and the discharge pressure regulated.

By extending the spindle 31, of the governing mechanism through the plate 22, the plate can be held in any suitable manner from rotation in the casing, and still be free to move towards the compression members.

The invention claimed is 1. A rotary pump comprising a casing having an intake and a discharge, co-acting eccentrically mounted pump members hav ing a compression space between them, a plate in juxtaposition to the side faces of said members having a discharge port in communication with the compression space, and means for advancing and retracting the compression spaces with relation to the dis charge port.

2. A rotary pump comprising a casing having an intake and a discharge, co-acting pump members rotatable in the casing and having intake and compression spaces between them, a laterally movable non-rotatable plate in juxtaposition to the side faces of the lpump members and having intake and disc arge ports communicating with said spaces, and means for adjusting said pump members to vary the position of the intake and compression spaces with relation to said ports.

3. A rotary pump comprising a casing having an intake and a discharge, co-acting pump members rotatable in the casing and having intake and compression spaces between them, a plate having intake and discharge ports communicating with said spaces, said plate being movable laterally toward the side faces of the pump members, and means for rotatably advancing and retracting the compression, spaces relatively to the discharge ports.

4. A rotary pump comprising a casing having an intake and a discharge, co-act ing pump members rotatable in the casing and having intake and compression spaces between them, a laterally movable but nonrotatable plate within the casing in uxtaposition to the side faces of the members and having an intake port and a discharge port communicating with the intake and compression spaces, and means for adjusting the pump members to advance or retractsa d compression spaces relatively to the discharge port.

5. A rotary pump comprising a cas ng having an intake and a discharge, co-actlng pump members rotatable in the casing an having intake and compression spaces between them, a non-rotatable plate having intake and discharge ports in communication with the intake and compression spaces respectively and bearing against the side faces of said members, means for ad usting the pump members in one direction to vary the position of compression spaces to the discharge port and increase the pressure, and means for-adjusting them in the opposite direction and decrease the pressure.

6. A rotary pump comprising a casing having an intake and a discharge, c o-act1ng pump members rotatablein the casing having intake and compresslon spaces between them, a non-rotatable plate ha v1ng lntake and discharge ports in communicatlon with the intake and compression spaces respectively, and bearing against the side faces of said members, means for rotatably ad usting the pump members for increasing or decreasing the discharge pressure.

7. A rotary pum comprising a cas ng having an intake and a discharge, co-acting pump members rotatable 1n the caslng and having intake and compression spaces between them, a plate with ports communlcating with the intake and compression spaces, a piston for rotatably ad usting the pump members to alter the,position of said spaces to the ports and vary the discharge pressure.

8. A rotary pump comprising a cas ng having an intake and a discharge, cp-actmg pump members rotatable m the casing and having intake and compresslon spaces between them, a plate having ports communicating with the intake and compression spaces, a' piston for rotatably ad usting said pump members in one d rection, and a spring for rotatably adjustlng them. 1n the tatably adjustable, a laterally mounted-now rotatable plate having intake and discharge ports and bearing against the side faces of said members, means for rotatably adjusting the pump members to regulate the discharge pressure, and a stop for limiting the adjustment.

10. A rotary pump comprising a casing having an intake and adischarge, co-acting pump members having intake and compression spaces between them, said pump members being rotatably adjustable, a plate, having a discharge port, co-operatin with said members, and means for rotatab y adjusting the pump members to advance and retract the compression spaces with relation to the discharge port and thereby regulate the discharge pressure. a

11. A rotary pum comprising a casing having an intake-an a discharge, co-acting pump, members rotatable in the casing and having intake and compression spaces between them, and a laterally movable but non-rotatable plate having ports in commuresaeee nication with the intake and compression spaces respectively adapted to be forced against the side faces of said members by the discharge ressure, said pump members being rotataby adjustable for advancing and retracting the compression spaces relatively to the discharge port.

12. A rotary pum comprising a casing having an intake an a discharge, pumping means rotatably mounted within the casing having intake and compression spaces, a non-rotatable plate movable laterally towards the side faces of saidipumping means and having a port in juxtaposition to the compression spaces, and means for changin the position of the compression space wit relation to said port.

13. A rotary pum comprising a casing having an intake an a discharge, co-actin pump members rotatable in the casing an having a compression space between them, a'laterally movable late in juxtaposition to the side faces of said members and forced against them by the discharge pressure from the compression space exerted against the back of the plate, and piston rings in the periphery of the plate contacting the inner wall of the casing, said ,pump members being rotatably adjustable to regulate the discharge ressure. v

' EBENEZER HILL. 

